🏪 Merchant Management API

A cleanly architected ASP.NET Core Web API for managing Merchants at Go Tap. This service implements CRUD operations, CQRS with MediatR, and validates country information using an external API.

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🚀 Features

• ✅ Create, Read, Update, and Delete merchants
• ✅ Clean Architecture with clear separation of concerns
• ✅ CQRS pattern using MediatR
• ✅ External API integration to validate merchant's country
• ✅ Asynchronous programming with async/await
• ✅ Testable and maintainable codebase
• ✅ JSON Enum support for Status

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📦 Technologies

• .NET 8 / ASP.NET Core
• MediatR
• FluentValidation
• HttpClientFactory
• Swagger / Swashbuckle (API Docs)

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🧱 Architecture Overview

This project follows Clean Architecture principles and includes the following layers:

├── Domain → Entities and Enums (pure business logic) ├── Application → CQRS (Commands/Queries), Interfaces, DTOs, Validators ├── Infrastructure → External API services, EF Core repository implementations ├── WebAPI → API controllers, DI configuration, middleware └── Tests → Unit tests for Application logic (handlers, services)

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🧾 Merchant Entity

public class Merchant : IdentityUser
{
    public string BusinessName { get; set; }
    public string Country { get; set; }
    public MerchantStatus Status { get; set; }
}

[JsonConverter(typeof(JsonStringEnumConverter))]
public enum MerchantStatus
{
    Pending,
    Active,
    Inactive
}

📡 External API Integration

Before creating or updating a merchant with a country, the API validates the country using:

🔗 https://restcountries.com/v3.1/name/{country} • ✅ 200 OK → Valid country • ❌ 404 Not Found → Returns 400 Bad Request with message: "Invalid country provided."

🛣️ API Endpoints

🔍 Get Merchant by ID GET /api/merchants/{id} • ✅ 200 OK → Merchant found • ❌ 404 Not Found → Merchant not found

📃 Get All Merchants GET /api/merchants • ✅ 200 OK → List of merchants

POST /api/merchants • Validates country before creation • ❌ 400 Bad Request → Duplicate email or invalid country • ✅ 201 Created → Merchant created

PUT /api/merchants/{id} • Accepts only updatable fields (e.g., PhoneNumber, BusinessName, Country, Status) • Ignores Id from body (only in URL) • ❌ 400 Bad Request → Invalid country • ✅ 204 No Content

DELETE /api/merchants/{id} • ✅ 204 No Content → Deleted successfully • ❌ 404 Not Found → Merchant doesn’t exist

🔧 Getting Started

1. Clone the repo git clone https://github.com/your-org/merchant-api.git

2. Restore packages dotnet restore

3. Run the API dotnet run --project MerchantApp.WebAPI

4. Visit Swagger UI https://localhost:/swagger

💡 Best Practices Followed • ✅ Clean Architecture • ✅ CQRS + MediatR • ✅ Async/await for I/O operations • ✅ Dependency injection everywhere • ✅ Resilient external API calls • ✅ Clear validation and error handling